In recent years, packaging containers and packaging bags have been required to exhibit sufficient sealing property for protection and storage of the contents, as well as easy unsealability (easy peelability) allowing them to be more easily opened by consumers. Various types of packaging films have been proposed that exhibit practical levels of both sealing property and easy unsealability.
For example, films that have been developed with the aim of providing easy unsealability include heat sealable laminated films composed of two layers that are blended layers of various acrylic acid copolymers and polyethylene (see Patent document 1), laminated films comprising 3-component blended layers of polybutene, polypropylene and polyethylene on a polypropylene base material layer (see Patent document 2), and multilayer films having a layer composed of a mixture of a methacrylic acid copolymer and polypropylene, and a polyethylene sealant layer (see Patent document 3).
[Patent document 1] Japanese Unexamined Patent Publication HEI No. 5-212835
[Patent document 2] Japanese Unexamined Patent Publication HEI No. 6-328639
[Patent document 3] Japanese Unexamined Patent Publication No. 2002-283513